Is the Prometheus sequel stalled out just because nobody knows how to follow that ending?

Is the Prometheus sequel stalled out just because nobody knows how to follow that ending?

Prometheus made more than $400 million worldwide (although it underperformed stateside) -- so a sequel seems like a safe bet. Except, according to one report, there's no forward movement on a sequel, because nobody can figure out what happens next after the first movie's somewhat baffling ending.